Hydrothermal Melting of Shales

1961 ◽  
Vol 98 (1) ◽  
pp. 56-66 ◽  
Author(s):  
P. J. Wyllie ◽  
O. F. Tuttle
Keyword(s):  
Water Vapour ◽  
Basaltic Magma ◽  
Liquidus Curve ◽  
Igneous Rocks ◽  
Granitic Magma ◽  
Refractive Indices ◽  
Chemical Characteristics ◽  
Complete Fusion ◽  
Partial Fusion

AbstractPT curves for the beginning of melting of five analysed shales in the presence of water vapour under pressure are 20° C. to 40° C. higher than the corresponding curve for granite. About 150° C. above the beginning of melting, the shales are half-melted; this is higher than the liquidus curve of most granites. Refractive indices of the quenched liquids (1·495–1·505) indicate a granitic or granodioritic composition. Quartz, cordierite, mullite, hypersthene, anorthite, etc., are developed in the partially fused shales. Partial fusion of shales by a granitic magma, even if superheated, would produce a liquid no more basic than granodiorite. The chemical characteristics of the shales are compared with average igneous rocks, and there appears to be no possibility that fusion of shales could produce a basaltic magma. Complete fusion would produce a melt with composition distinct from normal igneous magmas.

Geochemistry of bimodal amphibolitic—felsic gneiss complexes from eastern Massif Central, France

1995 ◽  
Vol 132 (3) ◽  
pp. 321-337 ◽  
Author(s):  
Bernard Briand ◽  
Jean-Luc Bouchardon ◽  
Houssa Ouali ◽  
Michel Piboule ◽  
Paul Capiez
Keyword(s):  
Crustal Contamination ◽  
Igneous Rocks ◽  
Chemical Characteristics ◽  
Continental Margins ◽  
High Grade ◽  
Transitional Stage ◽  
Crust Formation ◽  
Massif Central ◽  
Mantle Sources ◽  
Two Populations

AbstractHigh-grade basic and acidic meta-igneous rocks are widespread in the bimodal amphibolitic—felsic gneiss complexes, which are characteristic formations of the ‘Middle Allochthonous Unit’ from eastern and southern French Massif Central. The metabasites from the Lyonnais and Doux complexes are chemically diverse and range from N-MORB type tholeiitic to transitional types. The two populations are not related by fractional crystallization or crustal contamination processes and their chemical characteristics reflect differences in their mantle sources. An ensialic setting is supported by the crustally-derived character of some of the associated felsic rocks, but the presence of N-MORB-type metabasites argues for an extensional environment. This bimodal association compares well with the magmatism of rifted continental margins and may reflect a transitional stage between continental rifting and oceanic crust formation during the Cambro-Ordovician spreading event.

Cerium Tetrafluoride. I. Preparation and reactions

1965 ◽  
Vol 18 (7) ◽  
pp. 959 ◽  
Author(s):  
WJ Asker ◽  
AW Wylie
Keyword(s):  
Aqueous Solution ◽  
Water Content ◽  
Water Vapour ◽  
Hydrogen Fluoride ◽  
Low Temperatures ◽  
Cerium Dioxide ◽  
Lattice Parameters ◽  
Refractive Indices ◽  
Dissociation Pressure ◽  
Cerium Trifluoride

Pure anhydrous cerium tetrafluoride is best prepared by fluorinating cerium dioxide at 350-500�. A monohydrate can be obtained from aqueous solution in a variety of ways, but it cannot be dehydrated without decomposition. It loses water "zeolitically" in vacuum, showing relatively small changes in lattice parameters for loss of 70% of its water content. Thereafter the lattice collapses, forming well-crystallized cerium trifluoride and poorly crystallized "anhydrous" cerium tetrafluoride. The refractive indices of anhydrous monoclinic cerium tetrafluoride have been measured and its fluorine dissociation pressure at 500� shown to be less than 0.5 mm. At higher temperatures the tetrafluoride sublimes incongruently, and at 835-841� it melts with extensive decomposition into a fluorine-poor liquid and a fluorine-rich vapour. Cerium tetrafluoride is easily reduced to the trifluoride by ammonia and by water vapour at low temperatures. At higher temperatures it is quantitatively converted by water vapour to cerium dioxide and hydrogen fluoride. When heated with cerium dioxide it is reduced to the trifluoride with liberation of oxygen.

COMPARISON OF THE FUSION-FISSION AND QUASIFISSION MECHANISMS IN HEAVY-ION COLLISIONS

2009 ◽  
Vol 18 (04) ◽  
pp. 841-849 ◽  
Author(s):  
AVAZBEK NASIROV ◽  
GIOVANNI FAZIO ◽  
GIORGIO GIARDINA ◽  
GIUSEPPE MANDAGLIO ◽  
MARINA MANGANARO ◽  
...  
Keyword(s):  
Cross Sections ◽  
Theoretical Method ◽  
Heavy Ion ◽  
Evaporation Residue ◽  
System Model ◽  
Complete Fusion ◽  
Dinuclear System ◽  
Ion Collisions ◽  
Partial Fusion ◽  
Evaporation Residues

The decrease of the evaporation residue yields in reactions with massive nuclei is explained by an increase of the competition between quasifission and complete fusion processes and by the decrease of the survival probability of the heated and rotating nuclei against fission along the de-excitation cascade of the compound nucleus. The experimental data on the yields of evaporation residue, fusion-fission and quasifission fragments in the 48 Ca + 154 Sm reaction are analyzed in the framework of the combined theoretical method based on the dinuclear system concept and advanced statistical model. The measured yields of evaporation residues of the 48 Ca + 154 Sm reaction have been well reproduced and yields of fission fragments were analyzed using the partial fusion and quasifission cross sections calculated in the dinuclear system model. Such a way of calculation is used to find optimal conditions for the synthesis of the new element Z = 120 (A = 302) by studying the excitation functions of evaporation residues of the 54 Cr + 248 Cm , 58 Fe + 244 Pu , and 64 Ni + 238 U reactions. Our estimations show that the 54 Cr + 248 Cm reaction is preferable in comparison with the two others.

Petrogenesis of the Boundary intrusions in the Flin Flon area of Saskatchewan and Manitoba

1977 ◽  
Vol 14 (3) ◽  
pp. 444-455 ◽  
Author(s):  
Eric C. Syme ◽  
Richard W. Forester
Keyword(s):  
Basaltic Magma ◽  
Molar Ratio ◽  
Chemical Characteristics ◽  
Olivine Gabbro ◽  
Metasedimentary Rocks ◽  
Metavolcanic Rocks ◽  
Flin Flon ◽  
Group 2 ◽  
The Town ◽  
Felsic Rocks

The Aphebian Boundary intrusions are a group of lensoid, ultramafic to felsic rocks which occur in a N–NW trending zone 10 km long by 4 km wide centred on the town of Flin Flon. The intrusions were emplaced into Amisk metavolcanic rocks and Missi metasedimentary rocks. Field relationships, petrography, and chemical characteristics of the Boundary intrusions indicate that they are composed of three compositionally distinct, sequentially emplaced groups. From oldest to youngest, these are (1) a mafic augite- and biotite-bearing mela-dioritic group, (2) a felsic group ranging from leucodiorite to granodiorite, and (3) an olivine-bearing (wehrlite to olivine gabbro) group. The mafic group crystallized at relatively high [Formula: see text] and [Formula: see text], such that successive differentiates have increasing MgO/FeO ratios. Molar ratio diagrams clearly indicate that fractionation of augite, minor magnetite, and possibly subordinate olivine can account for the observed chemical variation of approximately 80% of this group, whereas the olivine-bearing group could only have formed by crystal fractionation of subequal amounts of olivine and clinopyroxene, and minor magnetite. The felsic group is chemically similar to the post-Missi granodioritic plutons and cannot represent SiO2-rich residual liquids produced solely by fractionation of augite and olivine from a basaltic magma.

Mafic-silicic layered intrusions: the role of basaltic injections on magmatic processes and the evolution of silicic magma chambers

1996 ◽  
Vol 87 (1-2) ◽  
pp. 233-242 ◽  
Author(s):  
R. A. Wiebe
Keyword(s):  
Basaltic Magma ◽  
Mafic Magma ◽  
Silicic Magma ◽  
Granitic Magma ◽  
Magma Chambers ◽  
Mechanical Mixing ◽  
Diffusive Convection ◽  
Type Granite ◽  
Mafic Magmas ◽  
Silicic Magmas

ABSTRACT:Plutonic complexes with interlayered mafic and silicic rocks commonly contain layers (1–50 m thick) with a chilled gabbroic base that grades upwards to dioritic or silicic cumulates. Each chilled base records the infusion of new basaltic magma into the chamber. Some layers preserve a record of double-diffusive convection with hotter, denser mafic magma beneath silicic magma. Processes of hybridisation include mechanical mixing of crystals and selective exchange of H2O, alkalis and isotopes. These effects are convected away from the boundary into the interiors of both magmas. Fractional crystallisation aad replenishment of the mafic magma can also generate intermediate magma layers highly enriched in incompatible elements.Basaltic infusions into silicic magma chambers can significantly affect the thermal and chemical character of resident granitic magmas in shallow level chambers. In one Maine pluton, they converted resident I-type granitic magma into A-type granite and, in another, they produced a low-K (trondhjemitic) magma layer beneath normal granitic magma. If comparable interactions occur at deeper crustal levels, selective thermal, chemical and isotopic exchange should probably be even more effective. Because the mafic magmas crystallise first and relatively rapidly, silicic magmas that rise away from deep composite chambers may show little direct evidence (e.g. enclaves) of their prior involvement with mafic magma.

Partial Suture Fusion in Nonsyndromic Single-Suture Craniosynostosis

2020 ◽  
Vol 57 (4) ◽  
pp. 499-505
Author(s):  
Michael K. Boyajian ◽  
Hanny Al-Samkari ◽  
Dennis C. Nguyen ◽  
Sybill Naidoo ◽  
Albert S. Woo
Keyword(s):  
Fusion Rate ◽  
Cranial Sutures ◽  
Complete Fusion ◽  
Age Group ◽  
Diagnostic Significance ◽  
Patient Age ◽  
Patient Âgé ◽  
Partial Fusion ◽  
Suture Fusion ◽  
Single Suture

Introduction: Partial synostosis of cranial sutures has been shown to have clinical and diagnostic significance. However, there is limited published information about how suture fusion progresses over time. In this study, we evaluate patients with nonsyndromic single-suture synostosis. We aim to define the incidence of partial versus complete suture fusion and whether a correlation exists between the degree of suture fusion and age. Methods: Two hundred fifty-four patients with nonsyndromic single-suture synostosis were evaluated. Preoperative computed tomography (CT) scans were rendered in 3-dimensions, all sutures were visualized and assessed for patency or fusion, and length of fusion was measured. Findings were grouped according to suture type (sagittal, coronal, metopic, or lambdoid), the degree of fusion (full, >50%, or <50%), and patient age at time of CT scan (0-90, 91-180, 181-360, or >360 days). Data were analyzed to correlate patient age versus the degree of suture fusion. Results: For all patients, 72% had complete and 28% had partial synostosis. Ratios of full to partial fusion for each suture type were as follows: sagittal 97:36, coronal 35:22, metopic 46:4, and lambdoid 4:10. The sagittal, coronal, and metopic groups demonstrated greater probabilities of complete suture fusion as patient age increases ( P = .021, P < .001, P = .001, respectively). This trend was also noted when all sutures were considered together by age-group ( P < .001). Conclusion: We note a partial suture fusion rate of 28.3%. Our analysis shows a correlation between the extent of suture synostosis and patient age. Finally, we demonstrate that different sutures display different patterns of partial and complete fusion.

The fluid dynamics of crustal melting by injection of basaltic sills

1988 ◽  
Vol 79 (2-3) ◽  
pp. 237-243 ◽  
Author(s):  
Herbert E. Huppert ◽  
R. Stephen ◽  
J. Sparks
Keyword(s):  
Continental Crust ◽  
Basaltic Magma ◽  
Source Region ◽  
Thermal Relaxation ◽  
Silicic Magma ◽  
Granitic Magma ◽  
Low Density ◽  
Magma Chambers ◽  
Theoretical Investigations ◽  
High Level

ABSTRACTWhen basaltic magma is emplaced into continental crust, melting and generation of granitic magma can occur. We present experimental and theoretical investigations of the fluid dynamical and heat transfer processes at the roof and floor of a basaltic sill in which the wall rocks melt. At the floor, relatively low density crustal melt rises and mixes into the overlying magma, which would form hybrid andesitic magma. Below the roof the low-density melt forms a stable layer with negligible mixing between it and the underlying hotter, denser magma. Our calculations applied to basaltic sills in hot crust predict that sills from 10-1500 m thick require only 2-200 years to solidify, during which time large volumes of overlying layers of convecting silicic magma are formed. These time scales are very short compared with the lifetimes of large silicic magma systems of around 106 years, and also with the time scale of 107 years for thermal relaxation of the continental crust. An important feature of the process is that crystallisation and melting occur simultaneously, though in different spots of the source region. The granitic magmas formed are thus a mixture of igneous phenocrysts and lesser amounts of restite crystals. Several features of either plutonic or volcanic silicic systems can be explained without requiring large, high-level, long-lived magma chambers.

A mechanism forming silicic segregations from basaltic magma discovered in igneous rocks of Western Sicily

1983 ◽  
Vol 120 (4) ◽  
pp. 321-329 ◽  
Author(s):  
G. Lucido
Keyword(s):  
Basaltic Magma ◽  
Liquid Immiscibility ◽  
Igneous Rocks ◽  
Silicate Liquid ◽  
Basaltic Magmas ◽  
Western Sicily ◽  
Basic Rocks ◽  
Silicate Liquid Immiscibility ◽  
Textural Evidence

Summary. Mechanisms forming silicic segregations from basaltic magmas are considered of primary importance when dealing with magmatic problems. However, the processes which give rise to silicic segregations from basaltic magmas are so far obscure. Fortunately, the discovery of spheroidal felsic masses in some basic rocks of Western Sicily throws light on this subject. To clarify the relationships between felsic and basic fractions particular attention has been paid to the interactions which occurred at their contact. Textural evidence indicates that the accretion mechanism of the Sicilian felsic segregations tends to obliterate the silicate liquid immiscibility effects and suggests that the formation of silicic segregations is a consequence of liquid unmixing phenomena.

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